Anemia is a complication of chronic renal failure (CRF) and end stage renal disease (ESRD) and it's predominant cause is a deficiency of erythropoeitin that is normally produced by the kidney. Injectable recombinant human erythropoeitin (EPO) has been used successfully in the treatment of anemia associated with CRF and ESRD, but it requires frequent administration. Novel erythropoeisis stimulating protein (NESP) is a new recombinant glycoprotein which has actions similar to EPO but has a 3-fold longer serum half life and could be given less frequently. NESP phase 1 clinical trial of using NESP in children to establish it's pharmacokinetic profile and safety in children. We plan to study the drug in approximately six children with CRF or ESRD, in the age range of 2-16 years. The design is a randomized cross-over trial in which each child will receive an intravenous or subcutaneous dose of the study drug initially, followed by the alternative injection mode after a 14 day washout period. Blood samples will be collected at various pre-determined intervals after the injection through an indwelling IV catheter whenever possible, to determine it's efficacy, pharmacokinetics and safety. Adverse events will be monitored throughout the study period of 5 weeks for each patient.